1. Field of the Invention
The present invention relates to the single frequency translator in a digital television (TV) broadcasting network, and more particularly, a distributed translator that can construct a data frame using information that is extracted from a received signal, instead of using an external control signal, and reset a memory of an encoder to thereby match data synchronization.
2. Description of Related Art
Generally, a translator may be installed in a region where weak signals are received from a main transmitter. The installed translator functions to solve reception difficulties and widen a transmission region of the main transmitter.
FIG. 1 is a block diagram illustrating a configuration of a general Advanced Television System Committee (ATSC) digital television (TV) translator according to a conventional art.
Referring to FIG. 1, the general digital TV translator includes a Vestigial Side Band (VSB) demodulation end 101 that receives a signal from a main transmitter (not shown) and demodulates the received signal, and a modulation end 103 that re-modulates the demodulated signal and transmits the re-modulated signal.
The VSB demodulation end 101 includes a tuner 105, an analog-to-digital (A/D) converter 107, and a VSB decoder 109.
The tuner 105 may receive a radio frequency (RF) signal from the main transmitter to select a desired channel.
The A/D converter 107 may convert an analog signal corresponding to the selected channel to a digital signal.
The VSB decoder 109 may perform VSB decoding for the digital signal to recover the signal to a transport stream transmitted from a transmission end.
The modulation end 103 includes a VSB modulator 111, an up converter 115, and a frequency synthesizer 113.
The transport stream may be input in the VSB modulator 111 to thereby go through a modulation process such as encoding, interleaving, and the like.
The up converter 115 may up convert a signal that is modulated by the VSB modulator 111.
FIG. 2 illustrates a configuration of a distributed translator using a particular packet according to the conventional art.
A distributed translation system according to the conventional art may insert a distributed transmission packet in a transport stream of a studio and may constitute a distributed transmitter and a distributed translator using distributed transmission packet information.
As shown in FIG. 2, the distributed translator using the distributed transmission packet information may include an RF receiving antenna 3, a band pass filter (BPF) 41, a high power amplifier (HPA) 62, another BPF 63, and an RF transmitting antenna 7. The distributed translation system using the distributed transmission packet information may only amplify an RF signal received by the RF receiving antenna 3 and then transmit the amplified RF signal.
Also, the distributed translation system using the distributed transmission packet information may remove an adjacent channel signal in the received RF signal using the BPF 41 and then amplify the RF signal using the HPA 62. The amplified RF signal may have channel noise included in the received RF signal. The adjacent channel signal that may be caused by the HPA may be removed using a channel filter. A signal in which the adjacent channel signal is removed may be transmitted.
The distributed translation system according to the conventional art may need to insert a distributed transmission packet in a transport stream. Therefore, there is a need for modifying the distributed translator and the broadcasting transmission system shown in FIG. 1.
FIG. 3 illustrates a configuration of a distributed translator that demodulates a symbol and then retransmits the symbol in a baseband according to the conventional art.
The distributed translator may demodulate a transmission symbol of a main transmitter up to a symbol level and convert the transmission signal to an RF signal and then transmit the converted RF signal.
As shown in FIG. 3, the distributed translator system that demodulates the transmission signal of the main transmitter up to the symbol level and converts the transmission signal to the RF signal and then translates the converted RF signal may include an RF receiving antenna 3, a BPF 41, an amplifier 42, a mixer 43 for an intermediate frequency (IF) conversion, an oscillator 45, an IF BPF 44, another mixer 61, an HPA 62, a BPF 63, and an RF transmitting antenna 7. The distributed translator may convert an RF signal received by the RF receiving antenna 3 to an IF and then convert the IF to the RF signal, amplify the converted RF signal and then transmit the amplified RF signal.
The conventional distributed translation system may require a modification or change for a transmitter-and-studio facility and may be inapplicable in a communication environment with a poor reception condition.